小编GY-*_*Y-Z的帖子

如果我不加括号地乘以得到华氏度数，我得到的数与乘以它们时得到的数不同。这是为什么？

#include <stdio.h>

int main (){
    double userinput, fahr1, fahr2;

    printf("Enter a number in Cels ");
    scanf("%lf", &userinput);

    fahr1 = userinput*(9/5)+32;
    fahr2 = userinput*9/5+32;

    printf("fahr1 = %f and fahr2 = %f \n", fahr1, fahr2);

    return 0;
}

输出：

#include <stdio.h>

int main (){
    double userinput, fahr1, fahr2;

    printf("Enter a number in Cels ");
    scanf("%lf", &userinput);

    fahr1 = userinput*(9/5)+32;
    fahr2 = userinput*9/5+32;

    printf("fahr1 = %f and fahr2 = %f \n", fahr1, fahr2);

    return 0;
}